The continuing trend of scaling down integrated circuits has forced the semiconductor industry to consider new techniques for fabricating precise components at sub-micron levels. Along with the need for smaller components, there has been a growing demand for devices requiring less power consumption. In the manufacture of transistors, these trends have led the industry to refine approaches to achieve thinner cell dielectric and gate oxide layers.
In dynamic semiconductor memory storage devices it is essential that storage node capacitor cell plates be large enough to retain an adequate charge (or capacitance) in spite of parasitic capacitance and noise that may be present during circuit operation. As is the case for most semiconductor integrated circuitry, circuit density is continuing to increase at a fairly constant rate. The issue of maintaining storage node capacitance is particularly important as the density of DRAM arrays continues to increase for future generations of memory devices. The ability to densely pack storage cells while maintaining required capacitance levels is a crucial requirement of semiconductor manufacturing technologies if future generations of expanded memory array devices are to be successfully manufactured.
Hemi-Spherical Grain (HSG) silicon enhances storage capacitance when used to form the storage node electrode without increasing the area required for the cell or the storage electrode height. The available methods include use of Low Pressure Chemical Vapor Deposition (LPCVD), engraving storage electrodes using poly film followed by P-diffusion utilizing POCl.sub.3 source gas, a mixture of spin-on-glass (SOG), coating the polysilicon with resist and HSG formation. The size of the grain formed from these processes is somewhat random and uncontrolled. The present invention, however, develops a method to control the actual grain growth during HSG formation.
U.S. Pat. No. 5,418,180, and U.S. Pat. No. 5,407,534, contain disclosure concerning HSG formation. U.S. Pat. No. 5,418,180 and U.S. Pat. No. 5,407,534, are hereby incorporated by reference as if set forth in their entirety.